It is known to manufacture thin plastic articles such as disposable drink cup lids by vacuum thermoforming. Such articles are manufactured by causing a web of extruded plastic sheet material to contact a metal die having the desired shape of the article formed into a surface thereof. Vacuum is applied to the platen surface through small holes to draw the plastic material over the contours of the die. The articles are thereafter separated from the web by die cutting and stacked and/or boxed using conventional automation devices.
It is also known to vacuum form logos and other indicia on the articles. Where the articles are lids, such indicia are typically formed of raised surfaces in a central deck area of the lid. Because thermoformed plastic lids are usually of one color, it can be difficult to see such vacuum embossed indicia clearly. To add definition, therefore, it is sometimes desirable that the raised surfaces of the embossed indicia may be colored. Alternatively, printing without raised surfaces can be utilized. Such printing is traditionally carried out by printing machinery separate from the thermoforming machinery, in a secondary operation, thereby raising manufacturing costs and extending run times.